Vehicle door latch



Patented Nov. 7, 1939 s UNITED STATES wenn VEHCLE DOOR LA'iCll-li HoldenW. Rghtmyer, Toledo, Uhio, assignor to The American Swiss Company,Toledo, Ohio,

a corporation of Ohio ApplicationAugust 9, 1937, Serial No. 158,138

1 Claim.

This invention relates to vehicle door latches particularly adapted foruse on automobile doors and an object is to produce a door latch of thischaracter which is relatively easy acting and in which the latch boltmay be more easily retracted against a substantially uniform springtension, thereby enabling the door to be closed readily upon slammingand facilitating retraction of the latch bolt by means. of the inside oroutside operated handles. l i

Another object of the invention is to provide a latch structure, whereinthe spring acts upon the bolt, in a manner sothat the tension of thespring is lessened during the initial retractile movement of the bolt,and is then increased during the continued movement of the bolt.

By way of illustration but not of limitation an embodiment of theinvention is shown on the accompanying drawing in which Figure 1 is aplan view of a vehicle door latch,

`a portion of the bolt plate being broken away to show the constructionof the rear end of the bolt head and the manner in which it is engagedby the spiral spring; and

Figure 2 is a fragmentary view of the latch shown in Figure 1 with thebolt partially retracted and showing the manner in which the spring endacts. i

The illustrated embodiment of the invention comprises a vehicle doorlatch having a back plate or case plate Il) formed with an upwardlyinclined flange ll, one end thereof which is provided with an openingthrough which the bolt l2 extends. Secured by rivets i3 to the rear endportion of the bolt l2 is a bolt plate Hl which has a rearwardlyextending portion I5 guided by a clip I6 for sliding movements relativeto the case plate I0. Disposed beneath the extension I5 is a plate Ilalso guided for sliding movements by the clip i6. The plate ll isengageable with a flange 2l in the bolt plate for retracting the bolt,and, as will hereinafter appear, can move forwardly to dog the outsideoperated roll back. The slide plate l1 is adapted to be connected by theusual link or strap to the remote control handle on the inside of thedoor, illustration and description of such remote control not beinggiven because the same is well-known to those skilled in this art.

Integral with the forward end of the slide plate Il and dependingtherefrom is an extension 20 which when the plate il is moved forwardlyor in non-bolt retracting direction, the extension engages beneath anarm 2l integral with the roll back cam 22. The usual `handle shaft iitsin the squared opening 23 in the roll back cam and normally it will beapparent that upon turning the roll back cam, the latter engages anabutment or flange 24 on the bolt plate Id thereby retracting the latchbolt. Such turning movement of the roll back cam` 22 will be blocked bythe extension 2D when the latter is disposed beneath the arm 2| as willbe readily understood.

A vertically movable slide 25 having a pin and slot connection 26 withthe case plate I!) is adapted to block retracting movement of the latchbolt when in lowered position, the iiange 2l' on the bolt plateextension 1'5 engaging the slide 25 when in such position.

The latch bolt is urged to its projected or latching position by aspiral spring 28, the end of which is .disposed between a pair of lugs29 on the case plate lll. The opposite or free end of the spring engagesthe rear face 30 of the bolt nose l2 and urges it to latching position.The surface at the rear end of the bolt acted upon by the spring lies ina general plane at right angles to the longitudinal axis of the bolt orto its plane of movement, and has a central or intermediate concaveportion 32 from Which slightly convex side portions emanate (33 and 3l),the latter portions gradually merging into the concave portion, wherebyabrupt or sharp portions or projections are eliminated. The spring has afree curved end 29a, which acts against the rear end of the bolt, and byvirtue of the formation of said end as describe-d, the tension on thespring is lessened during the initial retiactile movement of the bolt.

It is further to be noted that the curved end of the spring, when thebolt is shot, lies above the concave part of the surface, and thus actsagainst convex part 3l, consequently, when the bolt is retracted saidspring is moved downwardly and enters the concave part and then actsagainst the convex part 33. Thus, during initial retractile movement ofthe bolt, the tension on the spring is lessened, and then increased bythe convex part 33 upon continuance of such movement.

Also, when during such retractile movement the spring encounters theconvex part 3l, no abrupt or sudden action occurs.

It is to be understood that numerous changes in details of construction,arrangement and operation may be effected without departing from thespirit of the invention especially as defined in the appended claim WhatI claim is:

A vehicle door latch, including a case plate, `a

lo operating face, and means to anchor the spring to the case plate sothat its said curved spring end initially acts against one of the convexparts, and sequentially acts against the central concave part andfinally acts against the other of the convex parts, whereby the tensionof the spring is lessened during the initial retractile movement of thebolt and is then increased during the continued retractile movement ofthe bolt.

HOLDEN W. RIGHTMYER.

